starfive-tech/linux.git/init, branch rt-linux-release

rcu: Delay RCU-selftests

2023-11-06T11:24:46+00:00

Delay RCU-selftests until ksoftirqd is up and running. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner

mm/memcontrol: Disable on PREEMPT_RT

2023-11-06T11:24:46+00:00

559271146efc ("mm/memcg: optimize user context object stock access") is a classic example of optimizing for the cpu local BKL serialization without a clear protection scope. Disable MEMCG on RT for now. Signed-off-by: Thomas Gleixner

mm: Disable NUMA_BALANCING_DEFAULT_ENABLED and TRANSPARENT_HUGEPAGE on PREEMPT_RT

2023-11-06T11:24:39+00:00

TRANSPARENT_HUGEPAGE: There are potential non-deterministic delays to an RT thread if a critical memory region is not THP-aligned and a non-RT buffer is located in the same hugepage-aligned region. It's also possible for an unrelated thread to migrate pages belonging to an RT task incurring unexpected page faults due to memory defragmentation even if khugepaged is disabled. Regular HUGEPAGEs are not affected by this can be used. NUMA_BALANCING: There is a non-deterministic delay to mark PTEs PROT_NONE to gather NUMA fault samples, increased page faults of regions even if mlocked and non-deterministic delays when migrating pages. [Mel Gorman worded 99% of the commit description]. Link: https://lore.kernel.org/all/20200304091159.GN3818@techsingularity.net/ Link: https://lore.kernel.org/all/20211026165100.ahz5bkx44lrrw5pt@linutronix.de/ Cc: Mel Gorman Signed-off-by: Sebastian Andrzej Siewior Acked-by: Mel Gorman Link: https://lore.kernel.org/r/20211028143327.hfbxjze7palrpfgp@linutronix.de

mm: Allow only SLUB on PREEMPT_RT

2023-11-06T11:24:39+00:00

Memory allocators may disable interrupts or preemption as part of the allocation and freeing process. For PREEMPT_RT it is important that these sections remain deterministic and short and therefore don't depend on the size of the memory to allocate/ free or the inner state of the algorithm. Until v3.12-RT the SLAB allocator was an option but involved several changes to meet all the requirements. The SLUB design fits better with PREEMPT_RT model and so the SLAB patches were dropped in the 3.12-RT patchset. Comparing the two allocator, SLUB outperformed SLAB in both throughput (time needed to allocate and free memory) and the maximal latency of the system measured with cyclictest during hackbench. SLOB was never evaluated since it was unlikely that it preforms better than SLAB. During a quick test, the kernel crashed with SLOB enabled during boot. Disable SLAB and SLOB on PREEMPT_RT. [bigeasy: commit description.] Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner Signed-off-by: Sebastian Andrzej Siewior Acked-by: Vlastimil Babka Link: https://lore.kernel.org/r/20211015210336.gen3tib33ig5q2md@linutronix.de

bootconfig: init: Fix memblock leak in xbc_make_cmdline()

2021-10-11T02:27:40+00:00

Free unused memblock in a error case to fix memblock leak in xbc_make_cmdline(). Link: https://lkml.kernel.org/r/163177339181.682366.8713781325929549256.stgit@devnote2 Fixes: 51887d03aca1 ("bootconfig: init: Allow admin to use bootconfig for kernel command line") Signed-off-by: Masami Hiramatsu Signed-off-by: Steven Rostedt (VMware)

Merge branch 'work.init' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2021-09-24T17:18:07+00:00

Pull vfs fixes from Al Viro: "Followups to nodev root stuff from this merge window" * 'work.init' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: init: don't panic if mount_nodev_root failed init/do_mounts.c: Harden split_fs_names() against buffer overflow

init: Revert accidental changes to print irqs_disabled()

2021-09-22T20:02:30+00:00

Commit f8ade8dddb16 ("xsurf100: drop include of lib8390.c") accidentally changed init/main.c. Revert that part. Fixes: f8ade8dddb16 ("xsurf100: drop include of lib8390.c") Signed-off-by: Geert Uytterhoeven Signed-off-by: Linus Torvalds

init: don't panic if mount_nodev_root failed

2021-09-20T02:24:52+00:00

Attempt to mount 9p file system as root gives the following kernel panic: 9pnet_virtio: no channels available for device root Kernel panic - not syncing: VFS: Unable to mount root "root" (9p), err=-2 CPU: 2 PID: 1 Comm: swapper/0 Not tainted 5.15.0-rc1+ #127 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Call Trace: dump_stack_lvl+0x45/0x59 panic+0x1e2/0x44b ? __warn_printk+0xf3/0xf3 ? free_unref_page+0x2d4/0x4a0 ? trace_hardirqs_on+0x32/0x120 ? free_unref_page+0x2d4/0x4a0 mount_root+0x189/0x1e0 prepare_namespace+0x136/0x165 kernel_init_freeable+0x3b8/0x3cb ? rest_init+0x2e0/0x2e0 kernel_init+0x19/0x130 ret_from_fork+0x1f/0x30 Kernel Offset: disabled ---[ end Kernel panic - not syncing: VFS: Unable to mount root "root" (9p), err=-2 ]--- QEMU command line: "qemu-system-x86_64 -append root=/dev/root rw rootfstype=9p rootflags=trans=virtio ..." This error is because root_device_name is truncated in prepare_namespace() from being "/dev/root" to be "root" prior to call to mount_nodev_root(). As a solution, don't treat errors in mount_nodev_root() as errors that require panics and allow failback to the mount flow that existed before patch citied in Fixes tag. Fixes: f9259be6a9e7 ("init: allow mounting arbitrary non-blockdevice filesystems as root") Signed-off-by: Leon Romanovsky Reviewed-by: Christoph Hellwig Signed-off-by: Al Viro

init/do_mounts.c: Harden split_fs_names() against buffer overflow

2021-09-20T02:24:49+00:00

split_fs_names() currently takes comma separate list of filesystems and converts it into individual filesystem strings. Pleaces these strings in the input buffer passed by caller and returns number of strings. If caller manages to pass input string bigger than buffer, then we can write beyond the buffer. Or if string just fits buffer, we will still write beyond the buffer as we append a '\0' byte at the end. Pass size of input buffer to split_fs_names() and put enough checks in place so such buffer overrun possibilities do not occur. This patch does few things. - Add a parameter "size" to split_fs_names(). This specifies size of input buffer. - Use strlcpy() (instead of strcpy()) so that we can't go beyond buffer size. If input string "names" is larger than passed in buffer, input string will be truncated to fit in buffer. - Stop appending extra '\0' character at the end and avoid one possibility of going beyond the input buffer size. - Do not use extra loop to count number of strings. - Previously if one passed "rootfstype=foo,,bar", split_fs_names() will return only 1 string "foo" (and "bar" will be truncated due to extra ,). After this patch, now split_fs_names() will return 3 strings ("foo", zero-sized-string, and "bar"). Callers of split_fs_names() have been modified to check for zero sized string and skip to next one. Reported-by: xu xin Signed-off-by: Vivek Goyal Reviewed-by: Jan Kara Signed-off-by: Al Viro

memblock: introduce saner 'memblock_free_ptr()' interface

2021-09-14T20:23:22+00:00

The boot-time allocation interface for memblock is a mess, with 'memblock_alloc()' returning a virtual pointer, but then you are supposed to free it with 'memblock_free()' that takes a _physical_ address. Not only is that all kinds of strange and illogical, but it actually causes bugs, when people then use it like a normal allocation function, and it fails spectacularly on a NULL pointer: https://lore.kernel.org/all/20210912140820.GD25450@xsang-OptiPlex-9020/ or just random memory corruption if the debug checks don't catch it: https://lore.kernel.org/all/61ab2d0c-3313-aaab-514c-e15b7aa054a0@suse.cz/ I really don't want to apply patches that treat the symptoms, when the fundamental cause is this horribly confusing interface. I started out looking at just automating a sane replacement sequence, but because of this mix or virtual and physical addresses, and because people have used the "__pa()" macro that can take either a regular kernel pointer, or just the raw "unsigned long" address, it's all quite messy. So this just introduces a new saner interface for freeing a virtual address that was allocated using 'memblock_alloc()', and that was kept as a regular kernel pointer. And then it converts a couple of users that are obvious and easy to test, including the 'xbc_nodes' case in lib/bootconfig.c that caused problems. Reported-by: kernel test robot Fixes: 40caa127f3c7 ("init: bootconfig: Remove all bootconfig data when the init memory is removed") Cc: Steven Rostedt Cc: Mike Rapoport Cc: Andrew Morton Cc: Ingo Molnar Cc: Masami Hiramatsu Cc: Vlastimil Babka Signed-off-by: Linus Torvalds